<?php
	$text = "left right\r\nbottom";
    function clean($text) {
    	$text = addcslashes($text, "\x20\t");
    	$text = preg_replace('/[^\S\n]+/', ' ', $text);
    	$text = stripslashes($text);
    	return  preg_replace('/[^\S\n]+/', ' ', $text);
    }
    var_dump(json_encode($text));
    $text = clean($text);
    var_dump(json_encode($text));